contrib/bc/lib/testmul.c

   1 /* compute the crossover for recursive and simple multiplication */
   2
   3 #include <stdio.h>
   4 #include <time.h>
   5 #include "number.h"
   6 #ifndef VARARGS
   7 #include <stdarg.h>
   8 #else
   9 #include <varargs.h>
  10 #endif
  11
  12 /* from number.c ... */
  13 extern int mul_base_digits;
  14 /* extern int mul_small_digits; */
  15 extern bc_num _one_;
  16
  17 /* global variables */
  18 int test_n = 1000;
  19 int test_time = 30 * CLOCKS_PER_SEC;  /* 30 seconds */
  20
  21 /* Other things for number.c. */
  22 int std_only;
  23
  24 void
  25 out_of_memory()
  26 {
  27   fprintf (stderr, "Fatal error: Out of memory for malloc.\n");
  28   exit (1);
  29 }
  30
  31 /* Runtime error will  print a message and stop the machine. */
  32
  33 #ifndef VARARGS
  34 #ifdef __STDC__
  35 void
  36 rt_error (char *mesg, ...)
  37 #else
  38 void
  39 rt_error (mesg)
  40      char *mesg;
  41 #endif
  42 #else
  43 void
  44 rt_error (mesg, va_alist)
  45      char *mesg;
  46 #endif
  47 {
  48   va_list args;
  49   char error_mesg [255];
  50
  51 #ifndef VARARGS
  52   va_start (args, mesg);
  53 #else
  54   va_start (args);
  55 #endif
  56   vsprintf (error_mesg, mesg, args);
  57   va_end (args);
  58
  59   fprintf (stderr, "Runtime error: %s\n", error_mesg);
  60 }
  61
  62 /* A runtime warning tells of some action taken by the processor that
  63    may change the program execution but was not enough of a problem
  64    to stop the execution. */
  65
  66 #ifndef VARARGS
  67 #ifdef __STDC__
  68 void
  69 rt_warn (char *mesg, ...)
  70 #else
  71 void
  72 rt_warn (mesg)
  73      char *mesg;
  74 #endif
  75 #else
  76 void
  77 rt_warn (mesg, va_alist)
  78      char *mesg;
  79 #endif
  80 {
  81   va_list args;
  82   char error_mesg [255];
  83
  84 #ifndef VARARGS
  85   va_start (args, mesg);
  86 #else
  87   va_start (args);
  88 #endif
  89   vsprintf (error_mesg, mesg, args);
  90   va_end (args);
  91
  92   fprintf (stderr, "Runtime warning: %s\n", error_mesg);
  93 }
  94
  95 void
  96 out_char (int ch)
  97 {
  98   putchar (ch);
  99 }
 100
 101 /* Time stuff !!! */
 102
 103 int
 104 timeit ( bc_num a, bc_num b, int *n)
 105 {
 106   clock_t first;
 107   int i, res;
 108   bc_num c;
 109
 110   bc_init_num (&c);
 111   first = clock();
 112   *n = 0;
 113   do {
 114     for (i=0; i<test_n; i++)
 115       bc_multiply(a,b,&c,0);
 116     *n += test_n;
 117      res = (int) (clock() - first);
 118   } while (res < test_time);
 119   return res;
 120 }
 121
 122 int debug = 0;  /* Print debugging messages? */
 123
 124 int main (int argc, char **argv)
 125 {
 126   bc_num ten, num, expo, big;
 127
 128   int min, max, mid;
 129
 130 #if 0
 131   int smallsize;
 132 #endif
 133
 134   int n1, n2;
 135   clock_t t1, t2;
 136   float permul1, permul2;
 137
 138   /* args? */
 139   if (argc > 1)
 140     if (strcmp (argv[1], "-d") == 0)
 141       debug = 1;
 142
 143   bc_init_numbers();
 144   bc_init_num (&ten);
 145   bc_init_num (&num);
 146   bc_init_num (&expo);
 147   bc_init_num (&big);
 148   bc_int2num (&ten, 10);
 149
 150   if (debug)
 151     fprintf (stderr, "Timings are for %d multiplies\n"
 152                      "Minimum time is %d seconds\n", test_n,
 153              test_time/CLOCKS_PER_SEC);
 154
 155   /* Two of the same size */
 156   min = 10;
 157   max = 500;
 158
 159   if (debug)
 160     fprintf (stderr, "Testing numbers of the same length.\n");
 161
 162   while (min < max) {
 163     mid = (min+max)/2;
 164     if (debug) fprintf (stderr,"Checking %d...\n", mid);
 165
 166     bc_int2num (&expo, mid);
 167     bc_raise (ten, expo, &num, 0);
 168     bc_sub (num, _one_, &num, 0);
 169
 170     mul_base_digits = 2*mid+1;
 171     t1 = timeit (num, num, &n1);
 172     permul1 = (float)t1/(float)n1;
 173
 174     mul_base_digits = 2*mid-1;
 175     t2 = timeit (num, num, &n2);
 176     permul2 = (float)t2/(float)n2;
 177
 178     if (permul1 < permul2)
 179       min = mid+1;
 180     else
 181       max = mid-1;
 182
 183     if (debug) {
 184       fprintf (stderr, "n1 = %d :: n2 = %d\n", n1, n2);
 185       fprintf (stderr, "p1 = %f :: p2 = %f\n", permul1, permul2);
 186     }
 187   }
 188
 189   if (debug)
 190     fprintf (stderr, "Base digits crossover at %d digits\n", min);
 191   printf ("#define MUL_BASE_DIGITS %d\n", 2*min);
 192
 193
 194 #if 0
 195   mul_base_digits = min;
 196
 197   /* Small one times a big one. */
 198
 199   smallsize = min/2;
 200   bc_int2num (&expo, smallsize);
 201   bc_raise (ten, expo, &big, 0);
 202   bc_sub (num, _one_, &big, 0);
 203
 204   min = min / 2;
 205   max = 500;
 206
 207   if (debug)
 208     fprintf (stderr, "Testing numbers of the different length.\n");
 209
 210   while (min < max) {
 211     mid = (min+max)/2;
 212     if (debug) fprintf (stderr, "Checking %d...\n", mid);
 213
 214     bc_int2num (&expo, mid-smallsize);
 215     bc_raise (ten, expo, &num, 0);
 216     bc_sub (num, _one_, &num, 0);
 217
 218     mul_small_digits = mid+1;
 219     t1 = timeit (big, num, &n1);
 220     permul1 = (float)t1/(float)n1;
 221
 222     mul_small_digits = mid-1;
 223     t2 = timeit (big, num, &n2);
 224     permul2 = (float)t2/(float)n2;
 225
 226     if (permul1 < permul2)
 227       min = mid+1;
 228     else
 229       max = mid-1;
 230
 231     if (debug) {
 232       fprintf (stderr, "n1 = %d :: n2 = %d\n", n1, n2);
 233       fprintf (stderr, "p1 = %f :: p2 = %f\n", permul1, permul2);
 234     }
 235   }
 236
 237   if (debug)
 238     fprintf (stderr, "Non equal digits crossover at %d total digits\n", min);
 239   printf ("#define MUL_SMALL_DIGITS = %d\n", min);
 240
 241 #endif
 242
 243   return 0;
 244 }